rear breaks

How would i knoe if my rear drums from my 84 Rn60 havent been converted to later gen brakes. Reason i ask is because i checked my breaks and they arent actually beeing used the UTI professor said it was because the truck has a lift 2-3" spacers on the body (i thought that was stock) but thats causing a sensor for the rear breaks. In witch it is causing the breaks not to work. Said the solution was putting a bracket the same size of the spacers so they can funtion also one side has bigger shoes and the other one has smaller shoes but that's prob because they were installed wrong but only the one that has the bigger shoes grabs like bearly.

it's not uncommon to eliminate the LSPV and install a manual valve. you can also try and adjust the LSPV - I think I just changed the bend on the rod when I put 2" lift on my 93 and all is good, some people have to raise it with a plate.

I know it doesn't have to do with lspv but since non of the breaks were actually not getting worned out I thought it be because maybe the rear axle was swapped for a later version of it or the lspv because of the body height